RESUMEN
BackgroundRobust diagnostics, capable of detecting multiple variant of SARS-CoV-2 are necessary to mitigate the COVID-19 pandemic. In this study we directly compare the diagnostic capabilities of an LFI engineered with monoclonal antibodies (mAbs) originating from SARS-CoV-2 NP immunizations to the Abbott BinaxNOW COVID-19 Antigen CARD. MethodsHere we established a library of 18 mAbs specific to SARS-CoV-2 NP and used two of these mAbs (1CV7 and 1CV14) to generate a prototype antigen-detection lateral flow immunoassay (LFI). Samples consisting of remnant RT-PCR positive patient nasopharyngeal swabs preserved in viral transport media (VTM) were tested on the 1CV7/1CV14 LFI and the commercially available BinaxNOW test. Assays were allowed to resolve and results were recorded by two observers. FindingsA total of 98 remnant SARS-CoV-2 positive patient specimens were tested on both the 1CV7/1CV14 LFI and the BinaxNOW test. The 1CV7/1CV14 LFI detected 71 of the total 98 specimens, while the BinaxNOW test detected 52 of the 98 specimens. Additionally, the 1CV7/1CV14 LFI consistently detected samples with higher RT-PCR cycle threshold values than the BinaxNOW test. InterpretationThe 1CV7/1CV14 LFI outperformed the BinaxNOW test in the detection of BA.2, BA.2.12.1, and BA.5 Omicron sub-variants when testing remnant RT-PCR positive patient nasopharyngeal swabs diluted in viral transport media. BA.1 and BA.4 detection was comparable. The data suggest that mAbs derived from SARS-CoV-2 NP can aid in a more sensitive diagnostic immunoassay for COVID-19. FundingThe study was funded by the University of Nevada, Renos Research and Innovation Office, DxDiscovery, Inc. internal funds, and through AuCoin Laboratory internal funds. Research in ContextO_ST_ABSEvidence before this studyC_ST_ABSSince the onset of the pandemic, rapid antigen tests have proven themselves to be an accessible, accurate diagnostic platform. The widespread distribution of these tests has aided in curbing the COVID-19 pandemic. Data has shown that the tests manufactured at the beginning of the pandemic, utilizing monoclonal antibodies (mAbs) isolated from severe acute respiratory syndrome coronavirus (SARS-CoV), are less sensitive at detecting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron and Omicron subvariants. The reduced sensitivity can lead to diagnostic escape, and possible surges in COVID-19 caseloads Added value of this studyIn this study, a total of 98 remnant RT-PCR confirmed SARS-CoV-2 positive clinical specimens were tested on both a prototype rapid antigen test in the form of a lateral flow immunoassay (LFI) (referred to as the 1CV7/1CV14 LFI) and the available Abbott BinaxNOW COVID-19 Antigen CARD. The 1CV7/1CV14 LFI detected markedly more specimens (71 of 98) specimens than the BinaxNOW test (52 of the 98). Implications of all the available evidenceThis research suggests that that the use of mAbs isolated from immunizations with protein from SARS-CoV-2 may result in a diagnostic assay that is more sensitive in detection of SARS-CoV-2 Omicron subvariants, in comparison to the existing BinaxNOW COVID-19 Antigen CARD.
RESUMEN
COVID-19 (Coronavirus Disease 2019) caused by SARS-CoV-2 (Severe Acute Respiratory Syndrome CoronaVirus-2) continues to pose international public health threat and thus far, has resulted in greater than 5.6 million deaths worldwide. Vaccines are critical tools to limit COVID-19 spread, but antiviral drug development is an ongoing global priority due to fast spreading COVID-19 variants that may elude vaccines efficacies. The RNA-dependent RNA polymerase (RdRp) of SARS-CoV-2 is an essential enzyme of viral replication and transcription machinery complex. Therefore, the RdRp is an attractive target for the development of effective anti-COVID-19 therapeutics. In this study, we developed a cell-based assay to determine the enzymatic activity of SARS-CoV-2 RdRp through luciferase reporter system. The SARS-CoV-2 RdRp reporter assay was validated using a known inhibitors of RdRp polymerase, remdesivir along with other anti-virals including ribavirin, penciclovir, rhoifolin, 5CT, and dasabuvir. Among these inhibitors, dasabuvir (FDA-approved drug) exhibited promising RdRp inhibitory activity. Anti-viral activity of dasabuvir was also tested on the replication of SARS-CoV-2 through infection of Vero E6 cells. Dasabuvir inhibited the replication of SARS-CoV-2, USA-WA1/2020 as well as B.1.617.2 (delta variant) in Vero E6 cells in a dose-dependent manner with IC50 values 9.47 M and 10.48 M, for USA-WA1/2020 and B.1.617.2 variants, respectively). Our results suggests that dasabuvir can be further evaluated as a therapeutic drug for COVID-19. In addition, our assays provide robust, target-specific, and high-throughput screening compatible (z- and z-factors of > 0.5) platforms that will be a valuable tool for the screening SARS-CoV-2 RdRp inhibitors. SignificanceSARS-CoV-2 has caused a major public crisis world has seen in recent history. Development of vaccines and emergency use authorization of anti-virals are helping in reducing the burden of SARS-CoV-2 caused hospitalization and deaths. However, there is still need for optimal anti-viral(s) that can efficiently block viral propagation, and targeting viral polymerase (RdRp) is an among the most suitable targets for clamping viral replication. In this study, we developed a cell-based assay to screen potential compounds capable of blocking RdRp activity. The efficacy of our assay was validated by using already approved anti-virals, which reduced RdRp activity and slowed the replication of two SARS-CoV-2 variants (WA1 USA-WA1/2020 and B.1.617.2) in a cell culture model. This confirmed that our system can be used for identifying potential anti-SARS-CoV-2 anti-virals.
RESUMEN
Variants of SARS-CoV-2 have mutations in the viral genome that may alter the accuracy of rapid diagnostic tests. We conducted analytical and clinical accuracy studies of two FDA-approved rapid antigen tests--SCoV-2 Ag Detect Rapid Test (InBios International, Seattle) and BinaxNOW COVID-19 Ag CARD; (Abbott Laboratories, Chicago)--using three using replication-competent variants or strains, including Omicron (B.1.1.529/BA.1), Delta (B.1.617.2), and a wild-type of SARS-CoV-2 (USA-WA1/2020). Overall, we found non-significant differences in the analytical limit of detection or clinical diagnostic accuracy of rapid antigen testing across SARS-CoV-2 variants. This study provides analytical and clinical performance data to demonstrate the preserved accuracy of rapid antigen testing across SARS-CoV-2 variants among symptomatic adults.
RESUMEN
The COronaVIrus Disease (COVID-19) is a newly emerging viral disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Rapid increase in the number of COVID-19 cases worldwide led the WHO declare pandemic within a few month after the first case of infection. Due to the lack of a prophylactic measure to control the virus infection and spread, early diagnosis and quarantining of infected as well as the asymptomatic individuals are necessary for the containment of this pandemic. However, the current methods for SARS-CoV-2 diagnosis are expensive and time consuming although some promising and inexpensive technologies are coming out for emergency use. In this work, we report the synthesis of a cheap yet highly sensitive cobalt-functionalized TiO2 nanotubes (Co-TNTs)-based electrochemical biosensor and its efficacy for rapid detection of spike glycoprotein of SARS-CoV-2 by examining S-RBD protein as the reference material. A simple, low-cost, and one-step electrochemical anodization route was used to synthesize TNTs, followed by an incipient wetting method for cobalt functionalization of the TNTs platform, which is connected to a potentiostat for data collection. This sensor specifically detected the S-RBD protein of SARS-CoV-2 even at very low concentration (range of 14 nM to 1400 nM). Additionally, our sensor showed a linear response in the detection of viral protein with concentration range. In summary, our Co-TNT sensor is highly effective in detecting SARS-CoV-2 S-RBD protein in approximately 30 seconds, which can be explored for developing a point of care diagnostics for rapid detection of SARS-CoV-2 in nasal secretions and saliva samples. AUTHOR SUMMARYSARS-COV-2 is currently a global pandemic on a scale that has not been experienced since the Spanish flu of 1918. One of the reasons why this pandemic virus has spread so quickly is because many infected individuals with SARS-CoV-2 remain asymptomatic and involuntarily transmit the virus before they come down with the symptoms. Therefore, uniform surveillance and quarantining of infected as well as the asymptomatic individuals could provide an effective measure to contain the spread of SARS-CoV-2. However, the current methods for SARS-CoV-2 diagnosis are expensive and time consuming although some inexpensive technologies are getting approvals for emergency use. Our manuscript reports the synthesis of a cheap yet highly sensitive cobalt-functionalized TiO2 nanotubes (Co-TNTs)-based electrochemical biosensor for rapid detection of spike glycoprotein of SARS-CoV-2. Our sensor is synthesized through one-step electrochemical anodization route, followed by an incipient wetting method for cobalt functionalization of TNTs platform. The readout of this sensor is an electrochemical signal collected through a potentiostat, which can be adopted for use through smartphone applications and the development of a point of care diagnostics for COVID-19.
RESUMEN
The newly identified pathogenic human coronavirus, SARS-CoV-2, led to an atypical pneumonia-like severe acute respiratory syndrome (SARS) outbreak called coronavirus disease 2019 (COVID-19). Currently, nearly 23 million cases have been confirmed worldwide with the highest COVID-19 cases been confirmed in the United States. As there is no vaccine or any effective interventions, massive efforts to create a postential vaccine to combat COVID-19 is underway. In the meantime, safety precautions and effective disease control strategies appear to be vital for preventing the virus spread in the public places. Due to the longevity of the virus on smooth surfaces, photocatalytic properties of self-disinfecting/cleaning surfaces appear to be a promising tool to help guide disinfection policies to control infectious SAR-CoV-2 spread in high-traffic areas such as hospitals, grocery stores, airports, schools, and stadiums. Here, we explored the photocatalytic properties of nanosized TiO2 (TNPs) as induced by the UV radiation, towards virus deactivation. Our preliminary results using close genetic relative of SAR-CoV-2, HCoV-NL63, showed the virucidal efficacy of photoactive TNPs deposited on glass coverslips, as examined by quantitative RT-PCR and virus culture assays. Efforts to extrapolate the underlying concepts described in this study to SARS-CoV-2 are currently underway.